Causes of white bright band after bell annealing of a tin-plated steel plate

After bell annealing of a tin-plated steel plate,a white bright band appearred on the edge of the steel plate.By means of macroscopic observation,glow spectrum detection,surface roughness detection,metallographic inspection,scanning electron microscope and energy spectrum analysis,the reasons for the white bright band on the edge of tin-plated steel plate were analyzed.The results showed that in the process of bell annealing,the trace oxygen in hydrogen and active elements such as manganese and silicon in the tin-plated steel plate underwent selective oxidation to form oxides,which were enriched on the surface of steel plate,and finally formed a white bright band on the edge of steel plate.